Fetal side (shiny): develops from the trophoblast; chorionic villi are projections from the chorion that embed into the decidua basalis (endometrium)

Maternal side (beefy): decidua basalis is the endometrium at the site of implantation and forms the maternal side of the placenta. It contain cotyledons with branching villi. This is the site of exchange between the maternal & fetal blood across the placental membrane

Fetal blood takes the oxygen and nutrients before before retuning to the fetus through the veins in the umbilical cord

Many harmful substances can cross the placental membrane and those drugs the FDA categorizes C,D, or X should not be taken during pregnancy

What is the role of progesterone during pregnancy?

First produced by the corpus luteum to maintain the uterine lining for implantation of the zygote

Produced by the placenta to reduce uterine contraction to prevent spontaneous abortion

What is the role of estrogen in pregnancy?

Stimulates uterine growth and increases the blood flow through the uterine vessels

Stimulates the development of the breast ducts to prep for lactation

Effects of estrogen not related to pregnancy includes increased skin pigmentation, vascular changes in the skin and mucous membranes, increased salivation

What role does hCG play?

Causes the corpus luteum to persist & continue the production of estrogen and progesterone to sustain the pregnancy

hCG is detectable in maternal blood as soon as implantation occurs (usually 7-9 days after fertilization)

Rapid rise in first trimester and then decreases

Basis for pregnancy test

What is human placental lactogen (hPL) and what does it do?

Decreases insulin insensitivity and utilization of glucose by mother, which helps to make more glucose available to fetus to meet growth needs

Stimulates breast development for lactation

Related to gestational diabetes

Also known as human chorionic somatomammotropin (hCS)

What are the two embryonic membranes and from what do they develop?

Chorion & amnion form the amniotic sac

Chorion: develops from the trophoblast and is the outermost membrane

Amnion: originates from the embryoblast. Its a thin protective membrane that surrounds the fetus. It contains the amniotic fluid and expands as the embryo grows until the fetus comes in contact with the chorion

Describe amniotic fluid, its development, and its circulation

Slightly alkaline (shows up on nitrazine paper)

Secreted from the developing embryo in early pregnancy

Water & Solutes move freely across the fetal skin until about 23-25 weeks

Fetal kidneys produce the amniotic fluid after the first trimester

Amniotic fluid is absorbed by fetal blood as it perfuses the surface of the placenta

Fluid moves in and out of fetal lungs

What is the purpose of amniotic fluid?

Cushions the developing fetus and umbilical cord

Temperature control for the fetus

Symmetrical growth of the fetus

Prevents adherence to the amnion for the developing fetus

Acts as a wedge during labor

Can be analyzed to determine fetal health

Describe the normal amount of amniotic fluid and what occurs when the amount is abnormal

Peaks at 800-1000ml during the 34th wk and then decreases to 500-600ml at term